Postprandial blush in multiphase bone scanning.

The presence of transient soft-tissue activity in the left side and the lower midportion of the abdomen on the early phases of the multiphase bone scan represents postprandial physiologic hyperemia of the small intestine. The bowel uptake was present in all 33 patients ingesting food between 15 min and 3.5 hr before scanning. In those patients who had not eaten within 4 hr of the study, only 25% demonstrated bowel activity. The observation of bowel uptake is important in differentiating a physiologic phenomenon from pathologic accumulations of activity. Pathology should be ruled out when bowel activity is not located in the usual left flank and lower mid-abdomen, or is present in a fasting individual.